Pandit Govind Ballabh Pant Memorial Lecture: II

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Similar Distinct Distinct ECOTYPE (ecological races) The same The same entity Genetic species only (Example: autoploidy; certain kinds of chromosomal repattering Fig. 11. Relationship between systematics, genetics and ecology Behind such a common genetic and ecological thread, there are the specific attributes of genetic diversity, life history traits, population dynamics including its genetic architecture which equips a species to interact with other species and environment. Genetic diversity also equips a species at the molecular level to generate new variation through the processes of mutation, recombination and natural selection, leading to elimination of some and selection of others. Thus a phenotype is the result of interaction between genotype and environment. The phenotypic characteristic of an individual are coded into the genes of a taxon which determines whether it is going to be miniscule virus or an amoebae, or a giant like squoia, elephant or a whale. Today’s biodiversity is, therefore, the result of mutation, recombination and natural selection having taken place during the last 3 billion years. Life began with a DNA molecule having properties of self-replication, mutation and recombination. Genetic diversity is, therefore a prerequisite for all biological evolution leading to diversity (see also Solbrig, 1991). Biodiversity can be reduced both by habitat destruction leading to failure of populations to recover from mortality caused by habitat disturbances, and also by competitive exclusion thus there is interaction between competitive exclusion and mortality due to habitat disturbance. According to Huston (1991), when these two opposing trends are balanced, there is maximum biodiversity at intermediate disturbance level. Intraspecific genetic diversity is the fundamental building block of maintaining biodiversity. The natural selection acts on this, and populations are refined to function as interacting units within communities and ecosystems. The genetic consequence of habitat fragmentation leads to restrictions in gene flow and may be, in course time, to genetic differentiation. The particular life form of a species is also the consequence of selection. Thus, there are pine forests in the Himalaya. These are essentially large populations of big individuals with long life and good seed dispersal. Such populations have high productivity and live in low habitat disturbances. Conversely low productivity and high habitat distrubances. Destruction occurs due to abiotic causes (like extreme climatic conditions, fire, floods, etc) or biotic causes; (like parasitism, disease, predation, herbivory etc.). These lead to a competitive advantage for smaller populations, of small individuals with short life cycles. There are many such correlations (Stebbins, 1950;Grant, 1958, Gadgil and Solbrig 1972). The measurement of diversity can be at the allelic level within individuals or species, or at the level of gene pool on a population. This diversity can be studied through RFLP and RAPD. Next follows species richness in a community 44
in particular habitat, finally there is richness of communities in an ecological zone. In any community or ecosystem there are “keystone species” which have direct or indirect effect on the survival of other species in an ecosystem. A simple relationship between habitat destruction and productivity in relation to life form and overall biodiversity is shown in Figure 12. Ecosystem dynamics is still not understood, nor are molecular mechanisms underlying higher categories. There are efforts to bring in molecular aspects in phylogenetic and taxonomic categories like species, genera, families and phyla. Both biosphere and ecosystems are amenable to natural and human induced changes; physical chemical, biological and environment. Ecosystem science is still in infancy. So far, it has been concerned with inventorization of megagroups of organisms and has overlooked the micro-organisms and marine biota altogether. It has also not paid attention to process underlying ecosystem/ biosphere transformation. A major question remains unanswered: as to what causes extinction of widespread dominance of a species? Are there any physiological, genetic and ecological attributes that lead to extinction or dominance? Systematic investigation on different aspects of this problem need to be taken up. Some of the usual aspects of study of ecosystems include inventroization and establishment of databases. This would enable to take stock of the present level of knowledge. Generally microorganisms have been left out of consideration in ecosystem studies. But now it must receive special attention. For the collection of raw data, use can be made of parataxonomists, provided however, there is clarity about the sampling techniques. In other words, it should be clear as to what, how and where to sample, so that one is clear about the sites and biotic groups to be maintained. Quality of data is considerable importance for proper monitoring. Besides enumeration of species their distribution and life forms, at the level of ecosystems, there is need to understand functions that these species perform regarding their capacity for nitrogen fixation, decomposition of organic matter and as saprophytes, pollinators grazers etc; this together with the capability of ecosystems to capture, store and transfer energy, nutrients and water e.g. the whole range of biogeochemical cycles need investigation. Finally, the ecosystem need to be evaluated in terms of the services that these render to humanity: clean air, water, quality of life and above all, resilience to change and capacity for regenerability (Solbrig, 1991). Some of the foregoing aspects are summarized in Fig. 13 45
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Page 5 and 6: the southern edge of the Asian cont
Page 7 and 8: languages from Pusthu to Kashmiri,
Page 9 and 10: Table 1. Biogeography of Himalaya B
Page 11 and 12: The Himalayan ranges as a whole vir
Page 13 and 14: species are Cedrus deodara, Picea s
Page 15 and 16: densa associated with Rhododendron
Page 17 and 18: This region has mild summer and har
Page 19 and 20: 1000m to over 4000m in western Hima
Page 21 and 22: maintaining the health of the conce
Page 23 and 24: - Transition from cold desertic con
Page 25 and 26: commonly known as the pitcher plant
Page 27 and 28: Added to it is a whole range of med
Page 29 and 30: existence, other are proposed. Thei
Page 31 and 32: exercise is most urgently called fo
Page 33 and 34: It may, however, be pointed out tha
Page 35 and 36: 6.1.3 Alpine pasture 6.2 Dry alpine
Page 37 and 38: into action on ground. Besides the
Page 39 and 40: Conservation: The endangered wild e
Page 41 and 42: well-recognized hybrids already in
Page 43: These discoveries brought out the i
Page 47 and 48: The Green Revolution Agriculture is
Page 49 and 50: with the Chipko Andolan (Hug-the-Tr
Page 51 and 52: National Biodivesity Conservation B
Page 53 and 54: • Draw up plans for both ex situ
Page 55 and 56: Goeddel, D.V. et. al. 1979. Express
Page 57 and 58: Nayar, M.P. 1977. Changing patterns
Page 59 and 60: - Panicum psilopodium - Setaria vir
Page 61 and 62: - Myrica esculenta - Rubus moluccan
Page 63 and 64: - R. moluccanus - R. paniculatus -
Page 65 and 66: Oil Seed - Brassica quadrivalvis Fi
Page 67 and 68: C.hookeri C.jainii C.lucida Chaerop
Page 69 and 70: O.subcapitata O.tingens O.wattii Or

Pandit Govind Ballabh Pant Memorial Lecture: II

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